Various types of knee braces are shown in the patent literature and are commercially available. The following constitute examples of prior art braces that deal with restricting anterior movement of the tibia: U.S. Pat. Nos. 4,9055,369 (Bledsoe et al.); 5,433,699 (Smith, III); 4,751,920 (Mauldin et al.) and 4,781,180 (Solomonow). The apparatus shown by Mauldin is a knee brace that has a first attachment portion to attach the brace to the wearer's thigh and a second attachment portion to attach the brace to the wearer's tibia and a hinge connected to the medial side of the first and second attachment portions by way of a thigh bar and tibia bar, respectively. An adjustable gearing mechanism located at the hinge permits the wearer to limit the amount of rotation of the tibia bar with respect to the thigh bar. However, this brace suffers from failing to be able to prevent anterior translation of the tibia by the application of posterior pressure directed at the tibia tubercle location. Instead, like its predecessors, the Mauldin apparatus attempts to limit tibial rotation by limiting medial hinge motion.
The apparatus shown by Solomonow is a knee brace having an upper framework attached to the thigh and a lower framework attached to the lower leg just below the knee. These two frameworks are hinged on the medial and lateral sides of the leg (bilateral hinge). A bell crank is pivotally connected to the lower framework. An adjustable screw coupled to one side of the bell crank engages an offset portion of the upper framework whenever the leg is extended. The other side of the bell crank is coupled to a tibial restraining strap. As the leg is extended, the lower framework and bell crank are rotated counterclockwise until the offset of the upper framework contacts the screw, rotating the bell crank in a clockwise direction and thereby tightening the tibial restraining strap against anterior movement of the tibia.
The apparatus as shown by Bledsoe et al. is a knee brace which also utilizes bilateral hinges to connect the thigh support and calf support sections. The bilateral hinges basically comprise adjustable drive plates that alternate the pivoting point of the thigh support and calf support throughout leg flexion and extension. By varying the pivot point at different points throughout leg extension, a counter shearing force is generated to reduce the shearing force created by the quadriceps muscle which cause the undesirable anterior shift of the tibia of the leg.
Other prior art knee braces are disclosed in U.S. Pat. Nos. 3,581,741 (Rosman); 5,277,698 (Taylor); 5,512,039 (White); 3,387,305 (Shafer); 4,240,414 (Theisler); 4,805,606 (McDavid, III); 4,961,416 (Moore et al.); and U.S. Pat. No. 4,854,308 (Drillio).
Examples of prior art knee braces which are commercially available are: Innovative Sports C.Ti., C.Ti..sup.2, C.Ti..sup.2 Lite, Edge, Edge Lite, Sentry, C180 and MVP all of which are sold by Innovation Sports, Inc. Of Irvine, Calif.; Cincinnati ACL which is sold by Brace Technologies, Inc. Of Cincinnati, Ohio, the OS-5 (TM) non-custom functional knee support which is sold by Omni Scientific, Inc. Of Martinez, Calif.; the Lennox Hill (TM) OTS Brace and Spectralite Brace which are sold by 3M Health Care of Long Island City, N.Y.; the SKO (TM) and TKO (TM) knee orthoses which are manufactured by Orthotic Consultants of Southern California; the ACL model knee brace which is sold by Townsend Design of Bakersfield, Calif.; the DONJOY 4-Point (TM), Gold-Point (TM), Playmaker (TM), and Defiance (TM) all of which are sold by Smith & Nephew Donjoy, Inc. of Carlsbad, Calif.; the Poli-Axial Osteoarthritis Brace which is sold by Generation Orthotics, Inc.; and, the ECKO (TM) II Extension Control Knee Orthosis which is sold by Orthomedics of Brea, Calif.
While the aforementioned patents seem suitable for their intended purposes, it would be a significant advance in the art to provide a knee brace assembly that applies posterior pressure on the wearer's tibia in response to extension of the wearer's leg through the use of a cross-strap that is positioned over the wearer's tibia, wrapped in crisscross manner behind the wearer's knee and attached to biased strap guides slidably mounted to the brace assembly.